Thirty-six patients with high anxiety were recruited. The subjects were divided into working memory training group and control group in a voluntary and random manner, with 18 individuals in each group. The training group was trained for 21 days of working memory, and the control group was not trained for working memory. The subjective emotion ratings and the ERP indicator late positive potential (LPP) of the two groups of participants were recorded, under three experimental conditions (watching negative images, cognitive reappraisal, attentional distraction). It was found that the LPP amplitude reduction was significantly higher for training group than control group specifically in the condition of cognitive reappraisal. This study showed that working memory training can improve the ability cognitive reappraisal and can be a potential intervention for promoting the emotional regulation of individuals with high trait anxiety.